1. Field of the Invention
The present invention relates to a probe pin and an IC socket with the same, the probe pin being used for the IC socket which electrically connects a semiconductor device as a first contact object, such as a semiconductor wafer, and a wiring substrate as a second contact object, and is used for electrical inspection of the semiconductor device.
2. Description of the Related Art
In a process of manufacturing semiconductor devices such as semiconductor wafers and integrated circuit packages (also referred to as “IC packages”), various tests are conducted for inspecting the presence or absence of defectives in the semiconductor devices. As one of these tests, an inspection has been known in which a test signal is sent to a semiconductor device as the inspection object to check the electrical characteristics of the semiconductor device. In general, such kind of test is conducted via an electrical-connection apparatus (hereinbelow, simply referred to as “IC socket”) for semiconductor device configured to electrically connect the inspection object and a wiring substrate such as a test board. As such an IC socket, an IC socket disclosed in U.S. Pat. No. 7,677,901 has been known, for example.
In the IC socket disclosed in U.S. Pat. No. 7,677,901, probe pins are used as contacts each including a plunger, which is formed by punching a sheet metal into a predetermined shape via a press work, and a coil spring unit. Each of the plungers constituting the probe pins includes a first portion and a second portion, and is bent in a square U-shape with a connecting portion between the first portion and the second portion. The plungers are housed vertically movably in their respective through-holes each having a small-diameter portion and a large-diameter portion and being formed in an insulating base plate which constitutes a socket base of the IC socket. In addition, each plunger includes upper contact strips with three contact points which are so spread a plane and which an external contact point of a semiconductor device come into contact with. Moreover, the plunger is housed in the through-hole in such a manner that the leading ends of the three contact points of the plunger project upward from the through-hole. Furthermore, the plunger includes lower contact strips with two contact points that can come into resilient contact with a slimly wound portion of a tight wound portion of the coil spring unit, which constitutes the probe pin and includes a spring portion configured to resiliently urge the plunger upward.
In recent years, along with the increase in the density of the external contact points arranged on the semiconductor device as the inspection object, a finer pitch arrangement (also referred to as “narrower pitch arrangement”) has been required for the probe pins (also referred to as “contacts”) of the IC socket. The probe pins of the IC socket disclosed in the description of U.S. Pat. No. 7,677,901 described above are excellent in reliability, durability, and stability in contact with the external contact points of a semiconductor device. However, each plunger is bent in a square U-shape with the connecting portion between the first and second portions, and thus the first and second portions are disposed with a gap therebetween. Accordingly, it is difficult to achieve a finer pitch in the arrangement of the probe pins.
An object of the present invention is to provide a probe pin and an IC socket with the same, the probe pin being used for the IC socket and achieving a suitability for a finer pitch arrangement thereof while having the reliability, durability, and contact reliability thereof impaired as little as possible from those of conventional probe pins.